For the purpose of extremely simply carrying out a pre-treatment such as sample preparation including extraction or concentration of a component of interest in a short time when performing a chromatographic analysis, it is intended that a column configured such that the inside of a narrow tube is provided with a porous body having open pore structures across the entire diameter of the tube and along an appropriate length of the tube is used and a sample containing a substance to be measured is allowed to pass through the column to retain and concentrate the substance to be measured within pores of the porous body in the column, and it is also intended to provide a method in which the above described process is conducted as a micro trap when carrying out the pre-treatment of the chromatographic analysis and then the removed substances are introduced into analytical means, a method in which a sample is introduced into a separation column after narrowing the sample band when introducing the sample into a liquid chromatograph, and a method for collecting atmospheric substances such as gaseous substances in the atmosphere within a tube by using a collection tube configured such that a porous body having open pore structures composed of inorganic, organic, or hybrid polymers is formed inside a portion or all of a blank tube, the tube having advantages that the tube can be inexpensively manufactured so as to have an extremely simple structure as the so-called passive sampler which does not use a power such as a motor, a multiplicity of the columns are simultaneously used to increase the number of measurements, the sample can be collected without variation, and resistance at the adsorbent is reduced because an air blowing pressure loss is low and a surface area is large as a collector.